The Royal Canadian Air Force has grounded its new fleet of Cyclone helicopters after one of the aircraft appears to have malfunctioned during a training flight last month in Nova Scotia.

A spokesperson for the Canadian Forces said Friday that on March 9, an order was issued to pause flights of the CH-148 Cyclone fleet after one of the three helicopters used for training purposes experienced a “momentary change in the descent rate.” As a result, pilot training on the new fleet is being delayed indefinitely while the Royal Canadian Air Force and Sikorsky, which built the helicopters, investigate the cause.